The present invention relates to a wind turbine blade comprising a first blade part and a second blade part, the blade parts being bonded by bonding means forming a bond.
Another aspect of the invention relates to a method for manufacturing a wind turbine blade the method comprising the steps of providing a first blade part and a second blade, and bonding the first and second blade parts by bonding means to form a bond.
Modern wind turbines have grown considerably in size over the last decades, and at present have blades with a length of up to 100 m, and even longer blades can be anticipated in the future. Wind turbine blades are typically arranged in sets of three on a hub to constitute a rotor. The rotor is in turn connected to a main shaft arranged in a nacelle on top of a tower. As an example, a rotor having blades of 100 m sweeps a rotor area of more than 31,000 m2.
With increasing size, the loads on the structure, for example the blades, increase considerably. One reason is that the energy received by the wind turbine increases with the square of the increase in blade length. Further, the wind speed will not be constant all over the rotor, and the blades will be subject to more variance of the wind with increased size of the blades. Local variance of the wind at different positions of the rotor area are due to wind shear, i.e., lower wind speed near the ground than higher up, turbulence, wind shade, etc. All these factors increase fatigue loads and extreme loads on the wind turbine.
In wind turbine blades made up of blade parts, one of the loaded areas is the bond bonding the first and second blade parts.
An object of the invention is to provide a wind turbine blade with increased resistance to loading.